An era of a new radio access (NR) technology is approaching, and the industry mainly proposes architectures of the following two wireless communications systems to address a problem of how to couple the NR technology to an existing wireless communications standard technology.
An architecture of a first wireless communications system is shown in FIG. 1, which is a scenario in which a Long Term Evolution (LTE) technology is tightly coupled to the NR technology. In FIG. 1, an eNB (evolved Node B) represents a base station in an LTE system, an EPC (Evolved Packet Core, evolved packet core) represents a core network of the LTE system, an NR node represents a base station in an NR system, and the eNB is connected to the NR node by using an existing X5 interface. The tight coupling means that the NR node has no independent core network, and the NR node needs to transmit data with the help of the eNB in the LTE system. In such a tightly-coupled architecture, user equipment (UE) cannot directly access the core network by using the NR node, and instead, the UE needs to access the core network by using the eNB, causing an additional latency.
An architecture of a second wireless communications system is shown in FIG. 2, which is a scenario in which the LTE technology is loosely coupled to the NR technology. A fifth generation mobile communications technology (5-Generation, 5G) CN (core network) in FIG. 2 represents a core network of an NR system. The loose coupling means that an eNB and an NR node each have an independent core network. In such a loosely-coupled architecture, UE needs to use signaling of an LTE wireless communications standard to access the core network by using the eNB, and the UE needs to use signaling of another new wireless communications standard to access the core network by using the NR node. As a result, signaling is not unified, increasing signaling complexity.
Therefore, a new wireless communications system is required to resolve a problem that the foregoing two wireless communications systems respectively cause an additional latency and increase signaling complexity.